01-14-2015 09:14 AM - edited 03-05-2019 12:33 AM
Hi.
one question.
why bgp neighborship doesn"t establish when no dynamic routing protocol is enabled?
there four router.
A--------B-------C-------D
they all can ping.
No dynamic routing
static routing only enabled.
Configured bgp as 100 with A and D but bgp neighborshi didn"t establish.
am i missing something??
01-14-2015 09:25 AM
As long as the IP address of the peer is reachable it should be able to establish a peering.
If this was EBGP you may need to add extra configuration because it expects a direct connection but it is IBGP because A and D are in the same AS so it shouldn't matter.
Can you provide more details ?
Jon
01-14-2015 09:37 AM
It was ibgp. Config was like
//A//
router bgp 10
nei 1.1.34.4(D address) remote-as 10
//D//
router bgp 10
nei 1.1.12.1(A address) remote-as 10
they can ping each other. But state, stUck in active
01-14-2015 09:41 AM
Should work as long as they all have routes to each other and it sounds like they do.
Did you try debugging BGP to see what is actually happening ?
Jon
01-14-2015 10:19 AM
From A side :
R1#ping 1.1.34.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.34.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 80/127/164 ms
R1#show ip route
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.12.0 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 [1/0] via 1.1.12.2
R1#ping 1.1.34.4
R1#sh ip bgp summary
BGP router identifier 1.1.12.1, local AS number 10
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.34.4 4 10 0 0 0 0 0 never Active
=======================================================
From D side :
R4#sh ip bgp summary
BGP router identifier 1.1.34.4, local AS number 10
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.12.1 4 10 0 0 0 0 0 never Active
R4#
there's no special log. i tested in my GNS3 and i can open 179 both side by using telnet
weird thing is that when i enabled ospf for all of this topology, BGP neighborship was established. that's why i asked this question.
/////////////////////////////////////
router ospf 1
net 0.0.0.0 0.0.0.0 a 0
////////////////////////////////////
01-14-2015 10:39 AM
If you send me your configurations I can lab it up for you and see if I get the same issue.
What might be worth testing first though is to take a copy of all the routing tables then remove the statics and enable OSPF and compare.
It might show you if some routes are actually missing.
Jon
01-14-2015 10:58 AM
I tested and found out something.
removed OSPF
A and D, they have default route like 0.0.0.0 0.0.0.0
so i added static route in A /* ip route 1.1.34.4 255.255.255.255 */
after that, BGP established. what's the issue ?? why can't run with default route? is this only GNS3 problem?
01-14-2015 11:27 AM
Well you learn something new every day :-)
Just did a quick search and apparently BGP will not use a default route when trying to establish a peering.
More specifically the BGP peer that initiates the connection cannot use a default route whereas the peer that receives the request can use a default route to reply to the sender.
Didn't know that, or if I did I have forgotten it.
Jon
01-14-2015 12:06 PM
Thank you : ) you save me : )
01-14-2015 12:29 PM
Hello
I didn't know that either - I guess I have read about it and not digested that little nugget of information
cheer Jon
res
Paul
01-14-2015 10:38 AM
Hello
does an extended ping work and if versa?
ping 1.1.34.4 source 1.1.12.1
also do do you have any acls denying tcp port 179
laastly if the peer isnt directly connected you need to use update source command
Res
paul
01-14-2015 10:38 AM
they can ping with source command and there's no ACL
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